1. Field of the Invention
The present invention is related to a face portion detecting apparatus in which a human face portion is irradiated by light and a desirable face portion is detected while suppressing an adverse influence made by a reflection image caused by an article having a luster reflection surface such as spectacles (glasses).
2. Description of the Related Art
Conventionally, various methods for detecting eye portions by using reflection images produced by irradiating near infrared rays have been widely utilized. For instance, Japanese Patent Laid-open No. 06-270711 discloses a method operated in such a manner that while the near infrared rays are irradiated to the human eyeball portion, the pupil region of the eyeball portion is detected, and then blinking actions are detected based upon the change of the shapes of this eyeball region.
FIG. 13 is, for example, a schematic block diagram of a conventional face portion detecting apparatus disclosed in Japanese Patent Laid-open No. 06-270711.
As indicated in FIG. 13, the eyeball portion of a car driver 112, which is illuminated by the light emitted from a light source 102, is photographed by a camera 101. A pupil extracting unit 106 extracts the pupil region of the eyeball portion from this photographed image, and then, the circular degree of this extracted pupil is measured by a circular degree measuring unit 107. Next, the shape change in this circular degree is recorded in a shape change recording unit 108, and an awaking condition judging unit 109 judges such a fact that the awaking condition of the car driver 112 is lowered based upon the shape change when both the blinking time duration and the blinking frequency are larger than, or equal to the given time/value. Then, when the awaking condition judging unit 109 judges that the awaking condition of the car driver 112 is lowered, a warning output unit 110 produces the warning sign.
Also, Japanese Patent Laid-open No. 09-081756 discloses the method operated in such a manner that a retina reflection image is extracted by a filtering processing, and this retina reflection image is reflected from the illumination which is arranged in the same axis as an optical axis of a photographing means.
FIG. 14 is, for example, a schematic block diagram for indicating an arrangement of another conventional face portion detecting apparatus disclosed in Japanese Patent Laid-open No. 09-081756.
As indicated in FIG. 14, this face portion detecting apparatus is arranged by a photographing unit A and an image processing unit B. In the case that the illuminance level of the portion located around a face is low by checking the output signal of an illuminance sensor 124, an illumination light 122 is irradiated to the facial region, and then, the image of the facial region is photographed by a camera 121. The acquired picture signal is A/D-converted by an A/D converting unit 126 into the digital picture signal, and then, the retina reflection image is extracted by performing the filtering processing in an image processing circuit 127, an image memory 128, and a CPU 133.
Furthermore, in the face portion detecting apparatus explained in Japanese Patent Laid-open No. 09-021611, since a predetermined angle is secured between the optical axis of an illumination means and the optical axis of a photographing means, adverse influences caused by the reflection of the spectacles or the like can be suppressed. The arrangement of this face portion detecting apparatus is substantially identical to that shown in FIG. 14.
On the other hand, Japanese Patent Laid-open No. 10-216234 discloses such a method that since the spectacles equipped with an infrared LED and a phototransistor is mounted on a human being, the blinking actions of the human being is detected so as to avoid that the human being falls into a doze.
In the above-explained detecting apparatus disclosed in Japanese Patent Laid-opens No. 06-270711 and No. 09-081756, however, in such a case that the human being wears spectacles, there are such possibilities that the eye portion cannot be correctly extracted due to the adverse influences caused by the reflection image, which occurs on the luster reflection surfaces of the spectacles.
This condition is represented in FIG. 15 and FIG. 16. As indicated in FIG. 15, when the image of the face to which an illumination light 102 is irradiated is photographed by a camera 101, there exists a reflection image 142 reflected from the lens surface of a spectacles 140 other than a retina reflection image 141 (See FIG. 16). As a result, there is a certain probability that the reflection image 142 reflected from the surface of the spectacle lens is erroneously detected as the retina reflection image.
Also, in the arrangement of the face portion detecting apparatus disclosed in Japanese Patent Laid-open No. 09-021611, since a given angle is secured between the optical axis of the photographing means and the optical axis of the illuminating means such that the adverse influences caused by such a reflection image reflected from the surface of the spectacle lens is intended to be suppressed. However, this suppression effect cannot be achieved, depending upon the angles of the head portion. Accordingly, there is such a possibility that the reflection image of the spectacles and the like appears in the image as illustrated in FIG. 16.
Furthermore, in the detecting apparatus disclosed in Japanese Patent Laid-open No. 10-216234, since the human being must wear the specific spectacles, the human being feels cumbersome, which is a problem.